"I don't have an e-mail address. As much as I admire the Internet I suffer literally agoraphobia, which in it's original sense means a fear of the marketplace. I do not want to receive three hundred e-mail messages per week from strangers…"
- William Gibson

The Federation Ship Champion, manned by an all-male crew of eighteen experienced spacemen and carrying more than that number of male pioneers,
made the crossing under Lyle Drive in only nineteen days. The Champion landed just south of Lacus Soli, as Captain van Tromp intended to search for the Envoy.

Heinlein does not provide a description of how this propulsion system works; however, he compares it to the method still in use today:

At that time, only eight Terran years after the founding of the first human colony on Luna, any interplanetary trip made by humans necessarily had to be made in weary free-fail orbits, doubly tangent semi-ellipses--from Terra to Mars, two hundred fifty-eight days, the same for the return journey, plus four hundred fifty-five days waiting at Mars while the two planets crawled slowly back into relative positions which would permit shaping the doubly-tangent orbit-a total of almost three Earth years.